One characteristic of gasoline is that it has a relatively high volatility. Government entities issue regulations that specify maximum and/or minimum permissible levels or volatility. As one aspect of compliance with such regulations, it is well known that adding ethanol to gasoline will yield a mixture having different volatility and octane properties than the gasoline alone.
For example, in regard to volatility, adding ethanol to gasoline (1) increases what is commonly known as the Reid vapor pressure (RVP), (2) decreases what is commonly known as the vapor-liquid ratio temperature (T-V/L), and (3) decreases what is commonly known as the distillation temperature at the volume percent evaporated distillation point (T50). Thus, if an ethanol-free gasoline meets applicable regulatory requirements, but ethanol is then added and changes the volatility and octane properties, the resulting mixture may no longer comply with those regulatory requirements. As a result, refineries have traditionally prepared and distributed both (1) ethanol-free gasoline, and (2) a different gasoline blend that is configured to be mixed with ethanol but does not meet regulatory requirements until mixed with ethanol. While this approach has been generally adequate for its intended purposes, it has not been entirely satisfactory in all respects.
For example, in the distribution channel from the refinery to the ultimate consumer, it is necessary to transport, handle and store multiple grades of gasoline in order to service a market that desires or requires both ethanol-free gasoline and a gasoline-ethanol blend. In the event of an ethanol shortage at a distribution terminal carrying only gasoline formulated to be mixed with ethanol, the ethanol shortage would prevent the distribution terminal from conducting any sales of the gasoline in its inventory.